maybe a corrupted sound? try re-importing them a small batch at a time (4-5 at a time) and keep exporting to see if Node-Webkit breaks in a certain batch, then you can narrow down the culprit.
I took ya advice and found the culprit. There's no corrupt sound but I named one sound with "dog...bark bark" when i delete "..." from name the problem is gone. I waste my life on wrong file naming any way thank you very much,sir.